diff --git a/compiler/frontend/src/org/jetbrains/kotlin/idea/MainFunctionDetector.kt b/compiler/frontend/src/org/jetbrains/kotlin/idea/MainFunctionDetector.kt
index c9e60295128..df899dab8a0 100644
--- a/compiler/frontend/src/org/jetbrains/kotlin/idea/MainFunctionDetector.kt
+++ b/compiler/frontend/src/org/jetbrains/kotlin/idea/MainFunctionDetector.kt
@@ -101,6 +101,9 @@ class MainFunctionDetector {
                 return false
             }
 
+            val returnType = descriptor.returnType
+            if (returnType == null ||  !KotlinBuiltIns.isUnit(returnType)) return false
+
             if (DescriptorUtils.isTopLevelDeclaration(descriptor)) return true
 
             val containingDeclaration = descriptor.containingDeclaration